The present invention relates to a controlling method of a copying machine, more particularly, to a method for controlling the copying machine by the temperatures of a fusing device keeping it in a wait-reset state which is capable of the copying operation and in a wait state for preheating which is incapable of the copying operation.
In the copying machine of a type which heats and fuses a toner image transferred on the copying paper by the fusing device, should the copying operation be performed before the fusing device reaches a temperature high enough to fuse the toner, the toner image transferred specially on the copying paper will not be fused and the toner image will be readily damaged by hands, fingers and the like. The copying processing section, the conveying the copying paper section and so on are kept in a condition not to perform work as far as the temperature of the fusing device is still low. And the concrete measures to be taken are:
(1) Detecting that the fusing device has reached a preset temperature for fusing, a measure is taken for restoring the copying machine into the wait-reset state which enables to operates the copying operation section as well as the conveying the copying papers section and so on by detecting the signal, and
(2) a measure for restoring the copying machine to the wait-reset state after heating the fusing device for a certain period of time set by the timer.
According to the measure (1) mentioned above, inasmuch as the copying operation is available only after the fusing device reaches a preset temperature for fusing, a defective fusing can be precluded without fail. But it will take a long time for restoring the machine from the wait state to the wait-reset state. In other words, the time required to obtain copies after the copying operation is started by an operator will be protracted. Therefore, a greater improvement is desired from a clerical point of view, in which a speediness is seriously demanded.
On the other hand, according to the measure (2) mentioned above, while the setting time can be set relatively freely by the timer, etc., speeding of the copying operation can not be expected much, since setting of time is usually done with a sufficient safety factor considered in design so as not to cause defective copying. Moreover, despite the fact that a long heating time is required immediately after the start, a countermeasure taken so far is not sufficient and occasionally the trouble occurs in producing the defective copies. In order to obtain good fusing immediately after the start without fail, a long heating-up time for the fusing device is inevitably required after the initial starting state, thus the speeding-up of the copying operation may be greatly hindered.